1. Field of the Invention
The present invention relates to a method for synchronizing a wireless communication terminal with a neighbor cell, and more particularly to a method for rapidly synchronizing a GSM (Global System for Mobile communication) mobile communication terminal with a neighbor cell in a call connection state.
2. Description of the Related Art
It is well known in the art that a dual-band GSM mobile communication terminal or a GPRS (General Packet Radio Service) terminal is a GSM mobile communication terminal based on a GSM scheme.
The GSM mobile communication terminal can establish synchronization with a neighbor cell in a call connection state at only an idle frame of 26 multiple frames. In this regard, about 2 seconds are required for the GSM mobile communication terminal to establish synchronization with a new neighboring, even in a case where no errors occur.
FIG. 1 shows a comparison between timeslot arrangements of a serving cell and neighbor cell to illustrate a conventional method for synchronizing a GSM mobile communication terminal with the neighbor cell in a call connection state.
A TCH (Traffic CHhannel) is used to transmit speech and data signals, and includes a 26-multiframe with a length of 120 ms. Only 24 of the 26 frames are used for traffic, one is used for an SACCH (Slow Associated Control CHhannel), and the remaining one is not used. A terminal needs not perform transmission and reception at the same time since an uplink is allocated the third timeslot and a downlink is allocated a fourth timeslot in a TCH as shown in FIG. 1.
For example, in case of the second frame TCH 2, the serving cell starts reception Rx at a timeslot 0 and transmission Tx at a timeslot 3. Monitoring is then executed for measurement of power for a period of three timeslots 5 to 7.
In the neighbor cell, an FCCH (Frequency-Correction CHannel) burst is transmitted over a BCCH (Broadcasting Control CHannel).
Note that the neighbor cell is different in timing from the serving cell. In other words, as shown in FIG. 1, the timeslot 0 of the serving cell does not coincide with a timeslot 0 of the neighbor cell. Also, an FCCH burst is always transmitted at a timeslot 0 of a frequency 0 of an associated cell. That is, the FCCH burst of the neighbor cell is transmitted at the timeslot 0. At this time, the timeslot of the serving cell is at timeslot 1.
Attempting synchronization of the terminal with the neighbor cell at only the idle frame under the above condition is inefficient in that it requires a large amount of time. Later synchronization of the terminal with the neighbor cell may result in a failure in handover or an adverse effect on the quality of speech.